1. Field of the Invention
The present invention relates to automated warehouses and, in particular, to an automated warehouse which stores articles in a clean space.
2. Description of the Related Art
Reticles have been used for manufacturing electronic components, and are stored in a clean stocker placed in a clean room (See Japanese Unexamined Patent Application Publication No. 2008-30914, for example). In the clean stocker, the reticles are taken out of pods for storage, and the environment inside the clean stocker chassis needs to be kept from volatile impurities.
A clean stocker disclosed in Japanese Unexamined Patent Application Publication No. 2008-30914 is equipped with a clean gas supply unit, placed in the upper part of the chassis of the clean stocker, to supply clean gas in order to prevent the volatile impurities from entering the chassis.
The above conventional structure, however, requires the clean gas to be supplied to spaces for holding and transporting reticles taken out of pods; specifically, all the spaces inside a pod opener, inside a rotation rack, and between the pod opener and the rotation rack (transportation route for the reticles).
Here, a chemical filter for the clean gas supply unit is a very expensive and expendable, and the life of the chemical filter decreases with an increasing amount of airflow. In other words, in the case where the clean gas is to be supplied to all the above spaces, the chemical filter will have to be replaced in a short period of time and the resulting expenses for the storage will increase. The expenses will further increase in the case where the environment inside the chassis is to be kept from moisture as well as the volatile impurities (hereinafter referred to as “clean space”).